[The ESCRS study on antibiotic prophylaxis for endophthalmitis following cataract surgery].
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Biomedical subjects
Publications and source records attributed to C Ferrer.
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Given the scope and magnitude of the food supply in modern societies, there is no way to ensure that all foods are kept free from potential sources of contamination. Instead, food safety is enhanced by systematically concentrating upon minimizing opportunities for contamination at every point from food production and processing to distribution, preparation, and consumption. Although previous advances, such as pasteurization and refrigeration, and contemporary improvements in hazard analysis and control have significantly improved the safety of the food supply, foodborne disease remains a major cause of morbidity and mortality. Consequently, the food policy of the European Union and member states must reach the highest food safety standards in order to reduce the incidence of the illness produced by consumption of foods. To reach this goal, the new food regulation is in force since 2002 with the amendment through the hygiene package, which is in force since 2006. Risk Analysis forms the foundation on which food safety policy is based and an important part is aimed at microbiolgogical contamination. Additionally a European Food Safety Authority was established to carry out risk assessment and communication of food safety issues. At the same time, member states have created their own Food Safety Agencies working closely with the European Food Safety Authority. In this work, a description of the structure and work of the European Food Safety Authority and as an example the Spanish Food Safety Agency as well as key elements of the new regulation with special respect to the hygiene package is given.
Patients on chronic hemodialysis often portray high serum [K+]. Although dietary excesses are evident in many cases, in others, the cause of hyperkalemia cannot be identified. In such cases, hyperkalemia could result from decreased potassium removal during dialysis. This situation could occur if alkalinization of body fluids during dialysis would drive potassium into the cell, thus decreasing the potassium gradient across the dialysis membrane. In 35 chronic hemodialysis patients, we compared two dialysis sessions performed 7 days apart. Bicarbonate or acetate as dialysate buffers were randomly assigned for the first dialysis. The buffer was switched for the second dialysis. Serum [K+], [HCO3-], and pH were measured in samples drawn before dialysis; 60, 120, 180, and 240 min into dialysis; and 60 and 90 min after dialysis. The potassium removed was measured in the dialysate. During the first 2 hr, serum [K+] decreased equally with both types of dialysates but declined more during the last 2 hr with bicarbonate dialysis. After dialysis, the serum [K+] rebounded higher with bicarbonate bringing the serum [K+] up to par with acetate. The lower serum [K+] through the second half of bicarbonate dialysis did not impair potassium removal (295.9 +/- 9.6 mmol with bicarbonate and 299.0 +/- 14.4 mmol with acetate). The measured serum K+ concentrations correlated with serum [HCO3-] and blood pH during bicarbonate dialysis but not during acetate dialysis. Alkalinization induced by bicarbonate administration may cause redistribution of K during bicarbonate dialysis but this does not impair its removal. The more marked lowering of potassium during bicarbonate dialysis occurs late in dialysis, when exchange is negligible because of a low gradient.
PURPOSE: Demodex is a mite commonly found in eyelash hair follicles and sebaceous glands of healthy people. Due to the fact this mite has also been reported in many chronic cases of blepharitis, we aimed to investigate the incidence of infestation with this mite in healthy people and in patients with chronic blepharitis, in addition to evaluating the response to the different treatments used for blepharitis. METHODS: 105 subjects without blepharitis were selected as a control group and 20 subjects diagnosed as having chronic blepharitis were selected as patients. Epilated eyelashes were observed under microscope in both groups of patients. Those with overpopulation of mites were treated with ether lid and eyelash scrubs and 2% mercury oxide ointment. RESULTS: The incidence of Demodex infestation in the control group was 0.08 mites per eyelash, whereas in the patients with chronic blepharitis the incidence was 0.69 mites per eyelash; this difference was statistically significant (p=0.006). All the mites found were Demodex folliculorum except in one patient where the mite was identified as Demodex brevis. After 3-8 weeks of specific treatment the number of mites per eyelash decreased dramatically (0.03, with p=0.001). Two patients were intolerant of the therapy. CONCLUSIONS: In this study the incidence of Demodex in patients with blepharitis was very high, when compared with normal subjects, showing a clear association between blepharitis and Demodex infestation. Treatment with mercury oxide ointment was satisfactory in controlling the infection, despite difficulty in its application and occasional toxicity.
In this study, we examined the age-related changes on morphometric parameters and ultrastructure of seminiferous tubules, and on the expression of extracellular matrix proteins in lamina propria of Syrian hamsters. A significant decrease in the percentage of normal tubules and an increase in the percentage of hypospermatogenic and arrested maturation tubules was observed with aging. Aged animals showed a decrease in tubular diameter, tubular lumen, seminiferous epithelium volume and total tubular volume. However, the total length of seminiferous tubules was significantly increased with aging. The most important ultrastructural changes with aging were the thickening of the lamina propria, the presence of diverse abnormalities in the spermiogenesis process, degeneration of germ cells, and vacuolization and flattening of Sertoli cells showing abundant lipofucsin droplets and residual bodies. Laminin immunoreactivity was found along the lamina propria of seminiferous tubules both in young and aged animals. Fibronectin immunoreactivity was found along the lamina propria and blood vessels. Both laminin and fibronectin total volume of immunostaining per testis was increased in aged hamsters. In conclusion, the age-related changes in seminiferous tubules of hamster include: a decrease in tubular width and an increase in tubular length; widening of the lamina propria caused by a more extensive connective matrix between the peritubular cells and the basal membrane; and a strong disarrangement of the seminiferous epithelium, including germ cell degeneration and important alterations in both spermiogenesis and Sertoli cell structure.
The cellular mechanisms implicated in the atrophy of seminiferous epithelium in ageing are currently under debate, although recent reports suggest that apoptosis may be the primary mechanism implicated in aged germ cell loss. Other investigators have suggested that changes in spermatogonial proliferation are also involved. In the present work, the changes in proliferation and apoptosis in the seminiferous epithelium of aged (24 months) Syrian hamsters were examined in concert and compared with those in young (6 months) animals. Proliferation of germ cells was studied by bromodeoxyuridine labelling and apoptosis was assessed by transmission electron microscopy and in situ TUNEL labelling. Aged animals showed a significant decrease in the numbers of total and proliferating spermatogonia plus preleptotene spermatocytes per unit volume and per testis and in the proliferative index (24.8 +/- 1.6%) compared with young animals (30.8 +/- 1.2%) (P < 0.05). The number of apoptotic spermatogonia plus spermatocytes per unit volume and the apoptotic index were significantly higher in aged animals (1.51 +/- 0.23% v. 0.77 +/- 0.04%; P < 0.05). Apoptosis was confirmed by morphological characteristics: condensation of the chromatin and nuclear fragmentation. In aged hamsters, tubular degeneration could be classified into several categories, showing an increase of apoptotic cells in tubular cross-sections characterized by maturation arrest in comparison with all other types. Spermatogonial proliferation was also diminished as seen in tubular cross-sections showing hypospermatogenesis, sloughing off of germ cells and maturation arrest. The results obtained in the present study suggest that the decrease in the proliferation of spermatogonia and the increase in apoptosis constitute two consecutive mechanisms correlated with the ageing of the seminiferous epithelium.
AIMS: To ascertain the prevalence of acute trachoma as a supposed endemic disease among infants in the Saharan refugee camps of Tindouf (Algeria) and to evaluate the efficacy of treatment with a single dose of azithromycin. METHODS: 527 children aged between 3 and 17 were evaluated in the camp schools in October 2001. All the children were clinically and microbiologically examined, including slit lamp checks of anterior segment and two conjunctival swabs, one for the detection of membrane lipopolysaccharide by quick immunoassay test Clearview Chlamydia MF and the other for the detection of specific DNA by chlamydia plasmid specific polymerase chain reaction (PCR) assay. After examination, a single dose of azithromycin was administered to each child. One month later samples from positive children and 12 random negative children by the first PCR were taken to perform a new PCR assay. RESULTS: Chlamydia trachomatis was suspected in 2.47% of the children, papillary hypertrophy being the most frequently seen clinical sign. Scarring changes secondary to trachoma were detected in 11.7% of the children. Only four cases (0.8%) were positive to the immunoassay test and 12 cases (2.27%) were positive by PCR. After treatment a second PCR was performed on positive children and they were negative of chlamydia DNA amplification. However, one child who was negative and received the treatment was positive in the second PCR assay. CONCLUSION: Acute trachoma prevalence is much lower than expected among infants in this Saharan population. The possible reasons could be the recent improvements in hygiene and health care. Cicatricial trachoma is more frequent. The Clearview immunoassay test has very low sensitivity in the detection of this disease. A single dose of azithromycin is sufficient to treat chlamydial conjunctivitis. However, a programme of improvement in hygiene and health care is necessary to prevent re-infection.
Inversions of genetic segments during the evolution of Drosophila are well documented in the X chromosome and most autosomes, but little attention has been paid to chromosome 4, the smallest autosome or "dot chromosome" present in many Drosophila species. From our previous mapping we have defined probes that mark proximal, intermediate, and distal locations of chromosome 4 in D. melanogaster. In situ hybridizations on salivary gland polytene chromosomes with these probes show that the whole right arm, including genes within cytological region 101EF-102F, is inverted relative to D. simulans. We also used these probes to determine the orientation of the arm of the dot chromosome in nine species of Drosophila, including eight from the melanogaster subfamily. To account for the observed whole arm inversions of chromosome 4 in five of the nine species examined, we propose that three inversion events have occurred during the evolution of these species. These whole arm inversions may explain some of the unusual features of this chromosome.
Transforming growth factor-beta1 (TGFbeta1) downregulates tyrosinase in B16 melanoma cells by decreasing gene expression and the intracellular half-life of the enzyme, but does not block tyrosinase stimulation by alpha-melanocyte stimulating hormone (alphaMSH). In the presence of both agents, the enzymatic activity is intermediate between the one of cells treated with either agent alone. Here we show that TGFbeta1 equally inhibits the melanogenic activities of melan-a melanocytes and B16 melanoma cells, thus validating the B16 model. In both cell types, TGFbeta1 (10(-10) M, 48 h) inhibited to comparable levels tyrosine hydroxylation and melanin formation from L-tyrosine. Thus, the inhibitory effect is exerted mainly at the rate limiting step of the pathway. By means of quantitative image analysis techniques, we also studied the effects of TGFbeta1 and alphaMSH on melanosome number, volume density and maturation degree. alphaMSH (10(-7) M, 48 h) increased 7-fold melanosome volume density, whereas TGFbeta1 by itself had no significant effect. However, melanosomal volume density was intermediate in cells treated with both agents, as compared to control or alphaMSH-treated cells. Moreover, TGFbeta1 blocked the alphaMSH-elicited increase in the number of melanosomes. Control and alphaMSH-treated melanocytes contained more stage I+II premelanosomes and stage IV, fully melanized organelles than partially melanized stage III melanosomes. TGFbeta1 increased the percentage of stage III melanosomes. This trend was even more marked in cells treated with alphaMSH and TGFbeta1. The accumulation of incompletely melanized melanosomes is consistent with the inhibition of melanin formation activity by TGFbeta1 and with its hypopigmenting effect.
The mevinolin-resistance determinant, hmg, encodes the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and is a commonly used selectable marker in halobacterial genetics. Plasmids bearing this marker suffer from instability in Haloferax volcanii because the resistance gene was derived from the genome of this species and is almost identical in sequence to the chromosomal copy. In order to reduce the level of homologous recombination between introduced plasmid vectors and the chromosome of Haloferax, a homologue of the hmg determinant was obtained from the distantly related organism, Haloarcula hispanica. The nucleotide sequences of the wild-type genes (hmgA) of these two species are only 78% identical, and the predicted protein sequences show 71% identity. In comparison to the wild-type hmgA gene, the resistance gene from a mutant resistant to simvastatin (an analogue of mevinolin) showed a single base substitution in the putative promoter. Plasmids constructed using the new resistance determinant were stably maintained under selection in Hfx. volcanii and possessed very low recombination rates with the chromosome of this species. In addition, an improved strain of Hfx. volcanii was developed to overcome the plasmid instability and growth reduction observed in the commonly used WFD11 strain.
The goal of this study was to determine whether sequence analysis of internal transcribed spacer/5.8S ribosomal DNA (rDNA) can be used to detect fungal pathogens in patients with ocular infections (endophthalmitis and keratitis). Internal transcribed spacer 1 (ITS1) and ITS2 and 5.8S rDNA were amplified by PCR and seminested PCR to detect fungal DNA. Fifty strains of 12 fungal species (yeasts and molds) were used to test the selected primers and conditions of the PCR. PCR and seminested PCR of this region were carried out to evaluate the sensitivity and specificity of the method. It proved possible to amplify the ITS2/5.8S region of all the fungal strains by this PCR method. All negative controls (human and bacterial DNA) were PCR negative. The sensitivity of the seminested PCR amplification reaction by DNA dilutions was 1 organism per PCR, and the sensitivity by cell dilutions was fewer than 10 organisms per PCR. Intraocular sampling or corneal scraping was undertaken for all patients with suspected infectious endophthalmitis or keratitis (nonherpetic), respectively, between November 1999 and February 2001. PCRs were subsequently performed with 11 ocular samples. The amplified DNA was sequenced, and aligned against sequences in GenBank at the National Institutes of Health. The results were PCR positive for fungal primers for three corneal scrapings, one aqueous sample, and one vitreous sample; one of them was negative by culture. Molecular fungal identification was successful in all cases. Bacterial detection by PCR was positive for three aqueous samples and one vitreous sample; one of these was negative by culture. Amplification of ITS2/5.8S rDNA and molecular typing shows potential as a rapid technique for identifying fungi in ocular samples.
We have investigated the effect of 1-(5-oxohexyl)-3,7-dimethylxanthine or pentoxifylline (PeTx), a nonselective phosphodiesterase inhibitor, on osteoblastic differentiation in vitro by using two mesenchymal cell lines, C3H10T1/2 and C2C12, which are able to acquire the osteoblastic phenotype in the presence of bone morphogenetic protein-2 (BMP-2). PeTx induced the osteoblastic markers, osteocalcin and Osf2/Cbfa1, in C3H10T1/2 and C2C12 cells and enhanced BMP-2-induced expression of osteocalcin, Osf2/Cbfa1, and alkaline phosphatase. This activity was partially attributed to the fact that PeTx is able to enhance BMP-2-induced Smad1 transcriptional activity. Although PeTx clearly stimulates PKA in these cells, neither pretreatment of cells with the PKA inhibitor H89 nor transfection with the specific PKA inhibitor PKI prevented the induction or enhancement of osteoblast markers by PeTx, demonstrating that these effects were independent of PKA activation. On the other hand, PeTx induced the activation of ERK1/2 and p38 kinase pathways independently of the activation of PKA. Selective inhibitors of these MAPK cascades prevented the induction of osteoblastic markers in cells treated with PeTx, suggesting that the activation of these two pathways plays a role in the effect of PeTx on osteoblastic differentiation.
The study constitutes an approach to the knowledge of the epidemiology of cryptococosis in Spain. For detection of cases 167 Spanish hospitals were contacted. All cases included were accompanied by the correspondent isolate of Cryptococcus neoformans, together with clinical, demographic and mycological data. Results obtained from January 1998 to end of December 1999 are analysed and presented here. Fifty-six Spanish hospitals reported 58 cases of cryptococcosis; only 43 of them were adequately documented and accompanied by the clinical isolate. The results showed a higher incidence in males (88.4%) than in females (11.6%); being most frequently affected those between 30 and 40 years old (48.8%). The 84.6% (33) corresponded to new cases and 15.4% (6) to relapses of the disease. The HIV infection was the most frequent risk factor reported (86%) and, for 29.7% (11) of them, cryptococcosis was the AIDS defining disease. For the diagnosis, CSF analysis showed the best results (India ink; culture and antigen detection). All strains collected (100%) corresponded to C. neoformans variety neoformans. Serotypes distribution was 45.5% for serotype A and 22.7% for each of serotypes D and AD.
A protocol for intact DNA preparation from the basidiomycetous yeast Cryptococcus neoformans has been developed and applied to karyotyping C. neoformans isolates displaying different degrees of capsule formation. A total of 46 strains have been analyzed: 23 (50%) isolated from environmental samples (pigeon droppings), all of them belonging to C. neoformans var. neoformans; and 23 (50%) from clinical samples (human and veterinarian) including 10 isolates of C. neoformans var. neoformans and 13 isolates of C. neoformans var. gattii. Our results showed a global genome size ranging from 14.2 to 20.9 Mb for variety neoformans and from 7.9 to 16.8 Mb for variety gattii. The karyotype diversity was very high for variety neoformans (29 different patterns for the 33 analyzed strains) and lower for variety gattii (six different patterns for 13 strains). No grouping among variety neoformans strains from the same origin was found indicating very high genome diversity for this variety, irrespectively of the origin of the strains.
Although reinfusion of salvaged shed blood has become popular in major orthopaedic procedures, this blood saving technique is still controversial. In an effort to assess the functional and metabolic status of shed blood erythrocytes and the impact of postoperative shed blood reinfusion on allogenic blood requirements and patient's blood parameters, analyses of perioperative blood samples were performed in 28 consecutive orthopaedic patients undergoing spinal fusion, in which postoperative shed blood was collected and reinfused with the ConstaVac CBC II device. In comparison with a previous series of 31 patients, this procedure reduced allogenic blood requirements by almost 30% (P < 0.05), without any increase in postoperative complications. Postoperative shed blood presented lower haematological values and higher plasma-free haemoglobin (PFHB) levels than preoperative blood, without any disturbance in morphology, median corpuscular fragility (MCF) or erythrocyte adenosine triphosphate (ATP) and diphosphoglycerate (DPG) content. Serum concentrations of enzymes--glutamate-oxalacetate aminotransferase (GOT), glutamate-piruvate aminotransferase (GPT), creatine kinase (CK), lactate dehydrogenase (LDH)--and inflammatory cytokines (IL-1beta, IL-6) were elevated in shed blood. After reinfusion, there was no alteration in coagulation parameters or cytokine levels. Serum levels of some enzymes increased at the end of surgery and remained elevated at postoperative day 2 (CK) or 7 (GOT, LDH), with a higher increase if postoperative autotransfusion was used as a blood saving method. Therefore, caution should be taken when these serum enzyme levels are used for diagnosis. In conclusion, salvaged shed blood in orthopaedic procedures of the spine seems to be an excellent source of red cells which are not significantly damaged, keeping a normal functional and metabolic status, and reduces allogenic blood requirements without significant side effects.
The pigment pattern expression resides in the chromatoblasts of the embryonic skin. The differentiation of these chromatoblasts is influenced by specific local factors such a melanization inhibiting factor (MIF) and a melanization-stimulating factor (MSF). We reveal the presence of these factors by means of a series of experiments on the skin of the marine species of fish Dicertranchus labrax and Mugil cephalus, each with different pigment pattern, the former having a light skin and the latter a darker one. Media conditioned by exposure to dorsal and/or ventral skin, stimulates the melanization of Xenopus laevis neural crest cells throughout a 3 day assay period. Similarly conditioned culture media tested on B16-F10 murine malignant melanocytes, revealed a considerable influence in enzymatic activities: dopachrome tautomerase (DCT), tyrosine hydroxylase and dopa oxidase. The use of media in a dose response basis suggests that the conditioned media may contain both melanophore stimulating and inhibiting factors. The results obtained may actually reflect the resultant activity of the two factors present.
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We describe an enrichment of foetal cells from maternal blood with a combination of double density gradient and Magnetic Activated Cell Sorting (MACS) of CD71, glycophorin A (GPA), CD34 and CD36 antibodies labeled cells followed by fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes for determination of foetal sex.